I was talking to someone from Google who works on Bazel things, and he brought an interesting point: flaky tests are asymmetric in that they don't provide much value when they fail (since you don't know if the failure was due to flakiness), but they do provide a lot of value when they pass (because they presumable test something non-trivial.)

With this in mind, what Bazel does when a test is marked flaky is run it several times. This is a simple way of minimizing the effect of flakiness while still getting confidence from green tests.